Headlamp leveling actuators can be actuated for example electrically and serve the correction of the light being emitted by the light module of the headlamp, e.g. in case of a change of position of the vehicle. Herein, the headlamp leveling actuator tracks the movement of the vehicle so that the light module in the housing of the headlamp is temporarily or permanently in motion. Herein, the headlamp leveling actuator embodies a connecting link for at least one connection point of the light module in the housing of the headlamp, and position changes of the headlamp leveling actuator in the housing can be made by means of the adjustment device for adjustment purposes, which do also lead to a change in the distribution direction of the light emitted by the light module.
For the position of the cut-off line of the low beam of a headlamp, a high degree of accuracy is for example required in the vertical direction. If, for example, the alignment of the light module in the vertical direction changes by less than 1°, the cut-off line may, at a distance of 10 m, already have a deviation of more than 10 cm in the vertical direction. Hence, the holder arrangement of the light module in the housing must be executed very accurately, and despite the adjustment by means of the adjustment device, thermal expansion could occur, which inadmissibly displaces the light module in the housing.
DE 10 2010 048 989 A1, for example, shows a holder arrangement of a light module in the housing of a headlamp with a headlamp leveling actuator being held in a carriage element being embodied in a special manner in the housing of the headlamp, so that tilting of the carriage element effects the position of the light module in the housing of the headlamp as little as possible. Herein, it is also mentioned that the play between the guiding pegs and the guiding profiles between the carriage element and the housing in the headlamp can be unfavorably influenced by occurring marches of temperature, which in turn also has a negative influence on the positional accuracy of the light module in the housing.
The holder arrangement of the light module in the housing can for example form an upper connection point of the light module in the housing, via which the light module is fastened to the lower side of the light module in addition to two further connection points. If the holder arrangement , for example the headlamp leveling actuator, expands due to a rise in temperature, the light module in the housing of the headlamp can tip into the driving direction, causing the cut-off line to sink. If the holder arrangement and in particular the headlamp leveling actuator contracts due to a temperature decrease, for example due to low external temperatures, the light module tips against the driving direction, and the cut-off line can move upwards in an inadmissible manner
The headlamp leveling actuator is held in the housing of the headlamp via the adjustment device which can be operated manually once during the setting of the headlamp or during maintenance work to return the headlamp leveling actuator into the required position. This does not offer the possibility of a correction of transient, thermally caused changes to the position of the headlamp leveling actuator and therefore of the light module in the housing of the headlamp by means of the adjustment device.
From DE 10 2010 009 283 A1, an holder arrangement of a light module in the housing of a headlamp is known, which is embodied as a rigid reception point of the light module in the housing of the headlamp and which comprises a ball head around which the position of the light module can be changed. To compensate for thermally induced position changes of the reception point in the housing of the headlamp, expansion elements are proposed, which can be connected via extension lengths that are variable relative to one another, to compensate for thermally induced form changes of the housing, but also of the reception element itself. A change of the position of a headlamp leveling actuator due to thermal changes in the headlamp, however, cannot be corrected in a simple manner by such a thermo-compensation arrangement.